1. Field of the Invention
The present invention relates to an apparatus and method for improving picture quality. More particularly, the present invention relates to an apparatus and method for improving picture quality by synthesizing pictures having a high illumination difference.
2. Description of the Related Art
Recently, developers have conducted intensive research into a method for improving the quality of a picture or image captured by either a digital camera or a device having a digital camera module, resulting in the proposal of a variety of requisite devices, for example, a high-performance processor, a high-capacity memory for processing video or image data, and a controllable camera sensor, etc. Recently-manufactured digital cameras or devices each having a digital camera module have included the aforementioned requisite devices, resulting in a variety of results for improving the quality of a captured image or picture.
Many hybrid terminal devices each having a digital camera are currently being developed, such that the hybrid terminal devices are increasingly coming onto the market. A representative example of the hybrid terminal devices is a mobile phone (also called a hand-held device). The mobile phone has recently begun to include various functions. Particularly, an example of the current mobile phone is equipped with a camera, such that it can function as a digital camera or a camcorder. The mobile phone can basically capture a photo image simultaneously while performing a communication function. The most important thing for a user who takes a picture to know is how much the quality of a captured picture have improved since the introduction of mobile phones with digital cameras.
The digital cameras or the devices having such digital cameras use a variety of methods for improving the quality of a captured picture or image, and one representative example of the methods is a method for improving the quality of a picture or image having a high illumination difference. Typically, in the case of capturing a target object using a camera, exposure is controlled according to the peripheral illumination of the target object, such that controlled exposure is used. In this case, in case of adjusting the exposure to a target object having a low illumination, a background image having relatively-high illumination is saturated so that it is difficult to recognize the target object. Otherwise, in case of adjusting the exposure to the background image, an image of a target object having relatively-low illumination becomes too dark so that it is difficult to recognize the target object. Specifically, if an image is captured centering around a target object as shown in FIG. 1A, it is difficult to recognize a background image of the target object. Otherwise, if an image is captured centering around a background image of the target object, an image of the target object becomes too dark so that it is difficult to recognize the target object as shown in FIG. 1B. Therefore, if a captured image whose exposure is adjusted centering around the target object is synthesized with the other captured image whose exposure is adjusted centering around the background image under the aforementioned environment of a high illumination difference, and the synthesized result is properly processed, the best picture image having no lost image quality can be created in all the areas of the picture image.